> History of Microsoft Windows
> Bits and Bytes and other terms
> History of the Personal Computer

History of Microsoft's Windows Operating System (OS)

  Microsoft's Windows 1st announced (Nov)
  Windows 1.0 (Nov) - sold for $100
  Windows 2.0
Windows 386 (9 Dec)
  Windows 286 (June)
  Windows 3.0 (22 May)
  Windows 3.1 (Apr)
Windows for Workgroups 3.1 (Oct)
Windows NT 3.1 (Aug)  
Windows NT 3.5 (Sept) Windows for Workgroups 3.11 (Feb)
Windows NT 3.51 (June) Windows 95 (Aug)
- support for 32-bit technology
Windows NT 4 (Aug)  
  Windows 98 (June)
  Windows 98SE (5 May)
Windows (v5) 2000 (Feb) Windows ME (19 June)
- last version of the DOS based Windows OSs
Windows (v6) XP (25 Oct)  
Windows XP Service Pack 2 (Aug)
- bringing improvments in security



Windows (v7) Vista (Feb)


Bits, Bytes and other terms
~ a beginners guide ~

1 Kor Kilo = 1 Thousand or 1,000
1 M or Mega = 1 Million or 1,000,000
1 G or Giga = 1 Billion or 1,000,000,000
1 T or Terra = 1 Trillion or 1,000,000,000,000
1 P or Peta = 1 Quadrillion or 1,000,000,000,000,000
1 E or Exa = 1 Quintillion or 1,000,000,000,000,000,000

Computers store information in bits. A bit is a number that can be either 1 or 0. All digital devices boil down to this! Bits in themselves have limited use so a byte was defined which is a collection of 8 bits. Using the binary (0-1), as opposed to our dinary (0-9) number system a byte can represent any number between 0-255. These numbers are then used to represnt letters and other characters, e.g. the letter A is actually stored as the number 65 in a byte or as a computer knows it 01000010. Whenever we describe how much memory something is capable of storing we always describe this in terms of Bytes or 'B' for short. Numbers larger than 255 are made possible by joining 2 or 4 or 8 bytes together; these groups of bytes are called Words. A four byte word (equating to 32 bits) can represent any number from 0 - 4,294,967,295 (or about 4 Billion). Today these numbers are used to generate different amplitudes of electricity to produce the sounds from your CD player to your mobile phone, colours and dots you see on your computer screen, TV or DVD player and the movement from joysticks or gamepads, to robotic toys or machines.

Storing numbers:
Today computers store numbers in blocks of 32 or 64 bit Words, but we still describe the total amount of memory in Bytes. These numbers are stored in several ways. Initially they were stored as holes in paper tape (back in the 1950s), but now we store this information as either; pits on a CD or DVD, magnetic polarity on Hard Disk Drives; and most importantly as electrical charge stored on tiny transister circuites within a silicon chip. Always the information is stored as a collection of 1's or a 0's, on or off, North or South, hole or no hole. A CD for instance holds about 70 minutes of music, because it is really storing numbers, the information of the disk can be anything; files; pictures or sounds. A CD can store up to 800 Million Bytes (remember 1 Byte can store one letter even without compression this is a lot of information, equating to ) which equates to about 6.4 Billion Bits or 1's and 0's. In about another 2 years there will be a new disc to superceed the DVD which will be able to hold about 40 Billion Bytes (or 40 Giga Bytes as we call it in computer speak). Of course different types of media require different amounts of memory to store them; 1 letter needs 1 byte of information, a typical book if compressed would need 50,000 Bytes (50kB) which is about, a colour photo requires about 50,000 to 500,000 Bytes (500kB) depending on the detail required; a single (3 minutes of music) compressed requires about 6,000,000 Bytes or 6MB). So you can get about 7 hours of compressed music (MP3 format) on one CD. New ways of compressing sounds, pictures, movies and text are being developed all the time, squeezing more and more information into a fixed amount of memory.


Computers are not just about storing information but also about processing it. The more information you have and the numbers it takes to display, play or moving it, the faster the processor needs to be, the faster you need to be able get the information from memory. Hence the biggest factors in a computers speed are the 'Processor' (CPU chip), the speed of the Hard Disk and memory chips, and the speed of the Graphics processor (particualrly important for fast action games). Information is moved around in a computer on the stroke of a clock, the faster the clock the faster the computer, but the various parts of the computer must be able to keep up with the clock. Today clocks run at about a few Billion ticks or cylces per second, a cycle is refered to in Herts or Hz for short, so 1 Billion cycles per second is described as 1 Giga Herts or 1GHz. Hard disks are being pushed faster and faster, disks currently spin at about 7200 revs per minute, however it still takes about a hundredth of a second for the head to be moved to the right part of the disk to read the information (a long time in computer terms), hence the memory on silicon chips (or SIMMs or DIMMs as they are known) is still a lot faster as information can be retreived from anywhere in the memory in a fraction of a millionth of a second. And because SIMMs are more expensive for storing the same amount of information as Hard Disks SIMMs are used for a computer's short term memory and for processing information and Hard Disks for the long term memory storage.

Sending and receiving numbers:
Moving information from one device to another becomes important when the number of different types of devices is increasing exponantally along the amount of information to be moved. The more information can be moved from one place to another in a set amount of time the better. To compair these speeds we talk about the number of bits ('b' as opposed to Bytes 'B') that can be transfered per second this is abreviated as bps. To gage how many Bytes per second you must divide the amount of bps by about 10 (it would be 8 but 10 is easier and there are other overheads in communicating information). New faster international standards for transfering information are being thrashed out and agreed all the time. So there are many technologies to communicate information all with there own pro's and con's. Here are the most common ones below.

Modems (Modulate-Demodulate) To connect two computers together used to be done with serial ports and a couple of modems. The modems convert digital 1's and 0's to analogue waves like sounds to be transmitted over the telephone network. These started out being able to send just 300 bits of information a second, no good for todays needs. Today the lastest V.92 modem is able to send, with some clever digital magic, some 56,000 bps (or 56kbps) over the same telephone line. With the latest advances a new technology called ADSL Broadband has redefined the modem and allowed us tend up to 2Mps bits per second over a telephone line. however you must be with 4 miles of your local telephone exchange, so remote locations are unlikely to be able to use it. To connect your modem to a phone socket typically use RJ-11 or BT connectors.
USB (Universal Serial Bus) has also been designed to replace the 9-Pin Serial and 25-pin Printer ports and provide greater speed and flexability. USB v1.1 can send 12Mbps bits per second (or 12Mbps) and USB v2 can send at up to 480Mbps. It uses flexible shielded cables up to 5 meters in length and comes with different connector types to fit different sizes of devices. For more information go to
Infra-Red is light but further into the red part of the rainbow spectrum beyond which we cannot see. It uses LEDs to transmit this light and receive it. It is in all TV remote controls and was integrated into Laptops some mobile phones and other devices to enable them to send information to each other, but only by line of sight over short distances (i.e. several meters). Transmission speeds can be as high as 2Mbps.
Bluetooth a wireless technology using radio like signals to communicate over short distances (up to 15 feet). This technology is small and cheap so it can be fitted into the smallest devices for very little cost. For more information go to
Wireless (IEEE 802.11) is a newish standard to enable computers to communicate with each other at highish speeds and over greater distances (up to about 50 meters, less if signals have to go thru walls) without the need for phyisical connections. It uses radio like signals again, at a similar frequency to mobile phones or microwave ovens! Several speeds are supported from 11Mbps (for 802.11b) and 54Mbps (for 802.11a), however these speeds are about 3 times higher than you will actally get in practice due to the way the technology works.
Ethernet (IEEE 802.3) uses cables to connect devices together which allow information to be transmited at rates up to 10, 100 or 1000Mbps. Prices for this technology has been falling fast. And it is now possible to build very cheap high speed computer networks. Cable lenghts can also be faily long at up 100 meters. Many computers can be connected together by being plugged in a an Ethernet bridge or switche. And by connecting several bridges together even larger computer networks can be created.

IP (Internet Protocol) is a language that is used to help computers talk to each other over different types of technologies like those listed above. It is the language of the Internet. Carrying messages or information from one machine, on one side of the world, to another computer on the other side. To enable the many millions of computers to be able to talk with each other their must be large devices that act like junctions on a road network, directing information down different routes these devices are called IP Routers and Switches and it is these devices that allows the global network of the internet to function. (This is huge and complex subject and as it happens my speciality which I have taught for 6 years, anyway I will not bore you any longer).

History of the PC (Personal Computer) & related technology

Hard Disk
Memory Other enhancments
  N/A   8" floppy disk drive costs $1200
5.25" mini floppy introduced
1977   N/A    
1978   N/A    
1979   N/A   HP invent the first Inkjet printer
1980   N/A   Sony introduces 3.5" floppy or stiffy as they are called in South Africa
1981 4.7 Mhz N/A 16 KB Intel 8088 IBM PC
CGI 320x200 x4 colours
6 MHz 5 MB   Intel 286 CPU introduced
  10 MB   IBM PC/XT introduced (with 10 MB HD)
Sony 1.44MB 3.5" floppy Introduced
Intel brings out first portable computer (at 14kg)
      EGA introduced 640x360 x16 colours
HP introduces first LaserJet Printer
16 MHz 40 MB 1 MB
Intel 386 CPU introduced
      Epson introduce first Inkjet printer the SQ-2000
Standards for the E-mail format created
      3.5" Formfactor Hard Disk Drives appearing
VGA introduced 640x480 x 256 colours
      First CD-Roms start appear
Hayes introduces 9600 bps modem
      Intel 486 CPU introduced
Internet exceeds 100,000 clients
25 MHz 150 MB 4MB Tim Burners-Lee of CERN launches WWW
XGA introduced 1024x768 x 65k
      AOL for PCs introduced
First digital camera by Kodak/Nikon 1.3 Mega-pixels SLR
      Internet exceeds 1 million clients
66 MHz 340 MB 16 MB Intel Pentium CPU introduced
      4x speed CD-Rom drives introduced
(Yahoo starts up)
1995 founded
Casio introduce digital camera with LCD screen
      Internet exceeds 10 million clients
233 MHz 12 GB 32 MB AGP Graphics interface introduced
DVD-Rom's go on sale
Digital 1M pixel cameras hit the consumer market
333 Mz    

Intel Pentium II introduced
V.90 Modem introduced

500 MHz 25 GB 128 MB Intel Pentium III introduced
7200 rpm Hard Drives introduced
Wireless 802.11b introduced
  40 GB 128 MB Digital 3 Mega pixel cameras hit the consumer market
Microsoft found guilty of abusing its monopoly!
1.7G Hz     Intel Pentium 4 introduced
SerialATA interface for Hard Disks
Internet exceeds 100 million clients
2.4 GHz     Digital 5 Mega pixel cameras hit the consumer market
    256 MB Digital 6 Mega pixel cameras hit the consumer market


3.2 GHz 240 GB    
4 GHz x2 500 GB 2 GB Digital 12 Mega Pixel cameras & cheap Digital SLR
by 2012
~ 50 GHz ~ 5 TB 8 GB